This game was not ready for release
Stronghold 3 was released well before it was ready. There are many issues and bugs, and in the official forums Firefly studios has stated that while many patches are on the way, some key content will not be implemented. Here is the gist of the game as it stands now shortly after release:
You have to click around a unit a few times to actually select it, or zoom in close. You can drag a selection box around the area, but that is time consuming in combat. When in combat, ordering troops to attack a unit is a matter of waving the cursor around the enemy until you find the spot where you are given the attack cursor. Movement is much the same - click on a wall/platform to order your archers up, and often as not they end up exiting the gates to stand in front of the wall.
The AI is just dumb. A group of soldiers grouped together set on aggressive stance might attack an enemy unit attacking a comrade standing next to them, or they might just stand idle until they are attacked themselves. Pathing is also ridiculous. There are videos on youtube of wolves climbing vertical ladders up towers to slaughter the archers. Slaughter being the operative word: a typical wolf will chew through 2 or 3 spearman all by itself.
Lack of audible warnings/stats
Doesn't sound like a big deal, but when you lose half you villagers to a single wolf while you were looking elsewhere you realize how important it is. Also true for the lord unit - he can easily die if you don't keep an eye on him. There is no "select lord" button, so sometimes you have to spend precious time just looking for him. While all units have health bars, there are no stats displayed anywhere for any unit - ie: health.
No random skirmish mode. Developer's have confirmed it will not be added. As of the release date there is only a tiny selection of maps with only up to 4 players.
Maps are small and cramped. This is a castle building sim, but you cannot build a castle on most maps. The maps are small, the terrain is rocky or has other obstacles. Often you just build a series of separate walls. Space is always at a premium, and economy (food) takes up most of it.
Food is significantly out of whack. Most of the time villagers are on half rations because it takes a massive amount of food buildings to keep up with the food demand of full rations. This leads to unhappiness, which causes the villagers to leave. The happiness "equation" is out of whack as well - if there are empty beds (pop cap) then people are happy. If the beds are full, the people are unhappy. If there are more villagers than beds, they get really unhappy. Also, there is no "stockpile" of happiness. You could have a super happy village for quite awhile, then have a bad combination of events (which is frequent on some missions) which drives your happiness down, causing you to lose people, which throws your production chain out of whack.
The game is slow. Very, very slow. There is no speed up button. Troop movement is ridiculous and frustratingly slow. A wolf attacking one side of your town? By the time anyone (except archers - they're rockets) gets over there it's over.
Building is frustrating due to a number of circumstances on many maps. From not enough space, to not being able to push villagers aside, it can be an exercise in aggravation just waiting for an area to clear in order to place a building. "Filler" villagers wander aimlessly across the map, and you cannot place a building in a spot if one of them is walking through it. As the village grows the problem just gets worse.
Walls as tissue paper
As per the release version, arrows and spears can fly through walls. Therefore walls provide little defense, and no bonus to troops stationed on walls. In addition, it is fairly easy for a small group of armed peasants to tear down a big, fat stone wall. Makes siege weapons pointless.
There are many more, specific issues, but that gives you an overall idea of the quality of this game. It will be patched, but as of now it is a disaster.